BusyKnight of Texas questioned the reports claiming Varroa mite
    resistance to fluvalinate (Apistan R).  For verification of these
    claims, and unfortunately they are no longer rumours or anecdotal
    observations, you may refer to Apidologie 26(1) where Lodesani et al.
    confirm the 'ineffectiveness' of Apistan in Italy's Lombardy region.
 
    It has been claimed that this is the result of the inappropriate use
    of the product by applying the (cheaper) liquid formulation in various
    forms (eg. dipping cardboard strips and suspending them in the hive).
    However, inappropriate use also consitutes the placement of Apistan
    strips for prolonged periods, far exceeding the recommended treatment
    period as stated on the label.
 
    Here in Western Canada, there has been a rapid increase in the use of
    Apistan as Varroa has entered new areas.  But what has been happening
    is that many producers have adopted a management of convenience by
    installing strips during fall preparation and leaving them in until
    early spring.  Surely, an ideal environment towards the rapid
    development of 'Apistan-resistant' mites.   Also, the extended
    exposure may cause fat-soluble fluvalinate to migrate into the comb,
    potentially affecting bee brood development after successive years.
 
    What this means is that the threat of Apistan resistant mites may be
    much nearer than many of us think.  The repercussions of losing
    Apistan as a Varroa mite control agent will be serious.  Not only will
    producers resort to all kinds of "snake-oil" recipes but in the
    process, may end up contaminating their bees, equipment or honey.
 
    Indeed, in Europe several other products are registered for use
    including Bayverol (flumetrin).  The problem with flumethrin is that
    it also belongs to the family of synthetic pyrethroids, as fluvalinate
    does.  As has been observed in other mite pests, most notably the
    two-spotted spider mites, the build-up of resistance to one
    pyrethroid has often led to the simultaneous resistance to other
    closely related pyrethroids.  It would not be surprising if the
    Apistan-resistant mites of Lombardy display comparable levels of
    tolerance (resistance?) to flumethrin.
 
    While there is a genuine danger for the beekeeping industry to lose
    Apistan as a valuable tool of control, there appears no imminent
    arrival of other effective controls.  The only alternative available
    in Canada is formic acid which under favorable conditions may offer
    good control.  But formic acid, as cheap as it is, has to be handled
    with care and may not always be good to the bees.  It is therefore in
    everyone's interest to retain Apistan's effectiveness as long as
    possible:
 
        .       Use Apistan only when needed,
        .       Do not use alternate Apistan application methods,
        .       Always remove strips upon treatment completion,
        .       Do not re-use Apistan strips (I know it's tempting),
        .       Alternate with other (registered) products (eg. formic
                acid).
 
 
 
    Paul van Westendorp                 [log in to unmask]
    Provincial Apiarist
    British Columbia